ANGELA UKOMADU AND LIBBY GEORGE NIGERIAN police have used teargas to disperse dozens of people in the capital Abuja who had gathered to protest at alleged brutality by members of a special police unit, witnesses said. Protesters, some holding placards, ran as clouds of teargas hung in the air. Multiple people at the incident said on Twitter that police had fired the canisters. A spokesman for the police did not immediately respond to a message and call requesting comment. "They poured teargas on each and every one of us, it's so hot I had to put water on my face.…